Cannabis Oil Not Wise for Skin Cancer
A patient recently asked if Cannabis oil might be used to cure a small skin cancer.
Never having been asked this before, a thorough review of the available literature was carried out, but sadly there have been absolutely no published clinical trials to date so it is impossible to recommend this treatment.
Cannabinoids do bind to receptors which are present in many cells and there is some evidence in highly controlled laboratory circumstances that cannabinoids may inhibit some cancers. Sadly, there is also evidence that it may actually accelerate growth in others. There have been no useful trials in living humans and animal trials are not conclusive. The link at the end of this article gives more information and is maintained by the Uk Cancer Society so may be seen as a trusted and valid reference.
The proposed mechanisms of action of cannabis oil are plausible but unfortunately that does not make it safe or effective.
A search of the internet lists many sites where people claim to have had skin cancers cured by cannabis oil. This effect may occur for one of the following reasons:
- It is possible that the cannabis oil actually removed the cancer (a small proportion probably do get better as a result of treatment)
- The act of rubbing itself can stimulate immune reactions which can deal with some skin cancers.
- Some skin cancers will naturally go away on their own.
- The skin cancer may actually have been something else entirely (misdiagnosis of these lesions is common)
It is important to note that some of the cancers being illustrated as treated with the oil are of a type that can spread and potentially kill the patient. We feel that using a totally untrialled medication like cannabis oil in such circumstances is very unwise.
Cannabis oil is of course illegal in New Zealand so as a treatment option it is not valid in any case. Hemp oil contains cannabinoids but the concentration is much lower.
The good news is that not all skin cancers need surgery – some may be suitable for treatment with cream, especially in older patients and in many cases, the treatment is fully funded.
If you think you may have a skin cancer, please make an appointment – our doctors are very good at skin diagnoses and can give you proper treatment advice from leaving harmless things alone through creams to surgical removal if required.
We feel that it is important to point out that there is also good evidence that smoking cannabis (as opposed to a topical application) significantly increases the risk of lung and head and neck cancer, whether or not it is used in combination with tobacco. Whilst there may in the future be a place for medicinal use of cannabinoids, at present the evidence very strongly suggests that in almost all cases the side effects outweigh the benefits.
Addendum September 2016:
We have been asked to provide evidence to support the statement that cannabis smoking causes cancer. The spectrum of carcinogens in cannabis smoke is similar to that in tobacco smoke. It is the inhaling of burned leaves that results in tar deposition in the lungs. Cannabis smoke is generally retained in the lungs for longer than tobacco smoke which may also explain how cannabis causes chronic obstructive pulmonary disease. In a New Zealand study in 2008, it was found that cannabis smoking was associated with similar, or higher rate of lung cancer than tobacco smoking. Cannabis has also been associated with testicular cancer. Recent evidence casts doubt on the assertion that head and neck cancers are caused by cannabis smoking though it is important to note that the development of head and neck cancer is very slow and often occurs in association with other risk-factors. Some studies have shown an association and some have not. It remains our advice that the smoking of any substance is profoundly unwise and there is no reason to believe that cannabis is any safer than tobacco.
CBD’s Impact on Melanoma Cells
Hannah Yohe ’21 has read the news articles and seen the new businesses popping up touting the benefits of medical marijuana and cannabidiol, or CBD. She’s watched as friends and family purchase CBD products that offer promises of helping with joint inflammation or anxiety. While the York College Biology major is a believer in the health benefits of medical marijuana, she knew there was a lot of research ahead.
“I wanted to find the gaps in what still needed to be studied,” she says. “I’m really interested in this topic and thought I had an opportunity to dive into research while it’s still early in the process.”
Yohe found that melanoma, a form of skin cancer that can easily spread to other organs, was an area that had a lot of research gaps. York College had melanoma cells available in the lab, so Yohe just had to work to get access to CBD for her independent research project.
“You can’t just go out and buy CBD, despite what you see on the shelves of health stores or even at the gas station,” she says. “There are often other additives in it, and you need a pure form to be able to conduct research. Sigma-Aldrich biotechnology provided lab quality CBD for Yohe’s research. Finally, she could get to work.
A lot of people still have uncertainty about the health benefits of medical marijuana because they don’t understand it, Yohe says. While there are more than 100 chemicals in cannabis, the two most common are THC (short for tetrahydrocannabinol) and CBD. Both can be found in marijuana and hemp, although marijuana has more THC, which produces the high, and hemp has more CBD, which has other medicinal properties without the high.
The FDA has approved one CBD-based drug. Epidiolex is a treatment for several severe forms of rare childhood epilepsy. The National Institutes of Health clinical trials database shows more than 160 trials involving CBD that are either active or recruiting.
“It’s a subject that has a lot of opportunity for understanding,” Yohe says. “Getting into the research now is a great foundation for the work I could be doing in my career.”
While many people think of medical marijuana as a treatment for symptoms, such as anxiety or inflammation, Yohe found that CBD was actually instrumental in treating the root of melanoma. Other medical research shows CBD reduces the size of brain tumors, decreases growth in colon cancer and pancreatic cancer, and slows down blood vessel formation.
Yohe’s research backed up her theory that CBD could reduce the melanoma, but some of her experiments were cut short because of COVID-19. Despite not getting to all of her proposed experiments, she was able to use lab equipment specific to her research and learn some fascinating things about CBD.
“A lot of things we learn in the classroom can be theoretical, so you don’t see them in real life,” she says. “It’s cool when you can do the experiment yourself and get actual data and see that this stuff is real. We can test our theories and learn by doing.”